Don’t worry about the freshman fifteen, or the freshman 20 either. Just watch out for the fast food and junk food you consume.
If your you don’t do well with waking up in the morning don’t schedule morning classes, you have a hard time going to them.
Be a part of campus activities a clubs. Especially when you are very anti-social it breaks shells for many people. You make great friends and find out about lots of many useful resources that will befit your upcoming years.
Sit near the front of the class, trust me.
Make sure your communication with teacher counselors academic counsels and mentors. Their help is vital in college.
Try not to miss classes, one day can set you behind for a while.
And always introduce yourself to the professor, visit their office hours, make a connection make your self-known. Seriously it will help wonders when you feel more comfortable with the processor. Establish a connection, professors go on to write recommendations to things like career options and other opportunity. Take advantage of that!